In the last year there has been an epic drama unfolding. It transcends even the best political thrillers by John Le Carré or Roman Polanski. Over 40 arrests, the closure of the News of the World, the resignation of five senior public figures in quick succession, public questioning of media moguls in the House of Commons with the unannounced distraction of a custard pie, and the extensive examination of witnesses at the Leveson inquiry. Each episode is beamed into every home.

Intriguing and enthralling though it is, there are important underlying tensions between the need for public transparency in probing the truth about complex interrelations and the protection of individual rights. Already arguments are being voiced about whether the right to a fair trial for those who have been arrested has been compromised. The lawyer for Rebekah Brooks has made that clear, and doubtless this will be an ongoing contention. Although there have been no charges, an arrest marks the initiation of proceedings and therefore they are 'active' for all intents and purposes.

In large part the complaint is based on the prejudicial nature of the publicity surrounding the evidence – given not just at the inquiry but also at two Commons select committee hearings.

The right to a fair trial without prejudgment of the issues is fundamental. It is preciously guarded and respected. Article 6 of the European convention on human rights, now incorporated into UK domestic legislation, enshrines the basic elements. It is often useful to return to these first principles to temper the emotional charge of public debate. Key features are: "Everyone is entitled to a fair and public hearing within a reasonable time by an independent and impartial tribunal", "Everyone charged with a criminal offence shall be presumed innocent".

Article 6(3) sets out minimum conditions for a fair trial: prompt information about the accusation; adequate time and facilities for preparation; representation; examination of witnesses; and a free interpreter if necessary.

There is no express reference to prejudicial publicity, which will only begin to violate this provision if it can be shown to have rendered a tribunal partial or to have displaced the presumption of innocence. The real concern is where the material tends to suggest named or identifiable individuals are guilty of specific offences. For the phone-hacking arrestees, therefore, the question is whether at this stage the parliamentary committee or the inquiry has predetermined their guilt. Ultimately a court, if there were such material, would have to weigh up whether it was sufficiently close to the trial to make a fair hearing impossible.

There have been many such occasions, particularly where famous or notorious individuals have been involved. Clearly, the mere fact of favourable or unfavourable publicity is not enough. If it were, this would create a class of people immune to prosecution. On the whole, the UK courts have regarded the trial process itself as providing sufficient safeguards – for example, by warnings to jurors to ignore what they may have read, seen or heard in the media or on the internet. They take an oath to try defendants on the evidence presented to them. In exceptional cases at the start of proceedings, a judge may pose a question to establish whether a potential juror feels able to return an impartial verdict.

Our jury system is still the envy of the world, despite regular attempts to curtail it, and jurors must be trusted. Clearly it is fallible, mistakes are made, and jurors occasionally fail in their duties; but the overwhelming thrust of research suggests that jurors take their task very seriously.

Similar factors bear upon the risk of contempt of court. Strict liability arises where a publication creates a substantial risk that the course of justice will be seriously impeded or prejudiced. This applies just as much to the integrity of the prosecution as it does to the defence. Again, the crucial issue is whether the material prejudices the specifics of potential points relating to guilt or innocence at the moment of trial.

None of this will have been untrodden pastures for the lawyers advising the Commons select committee, the inquiry and those witnesses who were represented. And of course the high court judge himself has long experience at the criminal bar and on the bench.

What is at stake here is the real need to balance two competing public interests. On the one hand, the public right to know; and on the other, the preservation of a fair trial. To have delayed a public inquiry until the criminal investigations of unknown size into innumerable individuals had been completed would have been unacceptable. It has to be remembered that the unravelling revelations and resignations arising out of the hacking allegations touched upon the major institutions of our democracy. Public confidence in one of these had already been severely damaged by the parliamentary expenses scandal of 2009. A public inquiry some years down the line would have been rightly criticised as too little, too late. As is often said, justice delayed is justice denied, and nothing could be more essential for establishing justice in the exercise of power.

Criminal trials, if there are any, cannot be a substitute for a wide-ranging examination of the ethical standards and associations between the various so-called pillars of our society. Provided there is constant vigilance, and any final report takes account of any criminal proceedings, this will have been a service of historic and significant proportions accomplished for the benefit of better governance.